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Improved and updated documentation about accessibility

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git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/Temp_Accessibility@829769 13f79535-47bb-0310-9956-ffa450edef68
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Vincent Hennebert 2009-10-26 12:35:44 +00:00
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src/documentation/content/xdocs/trunk/accessibility.xml
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@ -29,13 +29,12 @@
<a href="http://en.wikipedia.org/wiki/Accessibility">accessibility</a>
features of Apache FOP.
<a href="http://www.section508.gov/">Section 508</a> defines accessibility in the context
of electronic documents for the US but it impacts also other countries.
of electronic documents for the USA but other countries have similar requirements.
</p>
<p>
These features are concentrated exclusively on PDF output
(Tagged PDF). There are certain implementation limitations that need to be observed
and certain actions are necessary by the content creator to ensure that FOP can create
a truly accessible document.
Accessibility features are available only for the PDF output format and there are some
implementation limitations. Also, certain actions must be undertaken by the content creator
to ensure that FOP can create a truly accessible document.
</p>
</section>
<section>
@ -43,7 +42,7 @@
<p>There are 3 ways to enable accessibility:</p>
<ol>
<li>
<strong>Command line:</strong> The command line option -a turns on accessibility.
<strong>Command line:</strong> The command line option -a turns on accessibility:
<code>fop -a -fo mydocument.fo -pdf mydocument.pdf</code>
</li>
<li>
@ -60,55 +59,55 @@
</li>
</ol>
<p>
As mentioned, enabling accessibility currently only changes the way PDFs are generated.
Internally, FOP maintains a reduced structure tree of the document so the target format
viewer can ultimately reconstruct the natural reading order of the document. This is
important for document readers that produce an aural representation of the content.
When accessibility is enabled, additional information relating to the logical structure of
the document is added to the PDF. That information allows the PDF viewer (or a
text-to-speech application) to retrieve the natural reading order of the document.
</p>
<p>
Hint: You may need to adjust the Java heap size in order to process larger files.
</p>
<note>The processing of the logical structure is memory-hungry. You may need to adjust the
Java heap size in order to process larger files.</note>
</section>
<section id="source">
<title>Changes to your XSL-FO input files</title>
<p>
Apache FOP cannot automatically generate accessible PDFs. Some of the work can only be
performed by the content provider. Following are some changes that may be necessary to
your XSL-FO content so the generate documents that are truly accessible.
your XSL-FO content in order to generate really accessible documents:
</p>
<ul>
<li>Table cells require a table row as the parent.</li>
<li>Table cells must have a table row as their parent.</li>
<li>
Ensure that the order of <code>fo:block-container</code> in a page corresponds to
Images must have an alternate text: use the <code>fox:alt-text</code> extension attribute
(in the <a href="extensions.html#fox-namespace">fox namespace</a>) on
<code>fo:external-graphic</code> and <code>fo:instream-foreign-object</code> to specify a
short text describing the image.
</li>
<li>
Ensure that the order of <code>fo:block-container</code> elements in a page corresponds to
the reading order.
</li>
<li>
Alternate text for images: The attribute <code>fox:alt-text</code> has been added
for <code>fo:external-graphic</code> and <code>fo:instream-foreign-object</code>.
</li>
<li>
Specify the natural language of the document using the language and country properties
(or via the xml:lang shorthand property).
(or via the <code>xml:lang</code> shorthand property).
</li>
</ul>
</section>
<section id="testing">
<title>Testing</title>
<p>
Accessible PDFs can be tested, for example, using Adobe Acrobat Professional. Its
Accessibility Check creates a report indicating any deficiencies with a PDF document.
Alternatively, you can just let a screen reader read the document out aloud.
Accessible PDFs can be tested, for example, using Adobe Acrobat Professional. Its
Accessibility Check feature creates a report indicating any deficiencies with a PDF
document. Alternatively, you can just let a screen reader read the document aloud.
</p>
</section>
<section id="limitations">
<title>Limitations</title>
<p>
Accessibility support in Apache FOP is relatively new, so naturally, there are certain
Accessibility support in Apache FOP is relatively new, so there are certain
limitations. Please help us identify and close any gaps.
</p>
<ul>
<li>
The natural language can currently only be specified on the page-sequence level. The
The natural language can currently only be specified at the page-sequence level. The
document language is derived from the language of the first page-sequence. It is
currently not possible to override the language inside the content below the
page-sequence level.
@ -118,7 +117,7 @@
</li>
<li>
SVG graphics (or images in general) are treated as a single figure. Text contained in
SVGs is not accessible. It's only possible to work with fox:alt-text.
SVGs is not accessible. It's only possible to work with <code>fox:alt-text</code>.
</li>
<li>
XSL-FO's role property is currently not supported. It could theoretically be used to
@ -129,28 +128,23 @@
The side regions (region-before, region-after etc.) are currently not specially
identified. Screen readers may read their content at page changes.
</li>
<li>
The accessibility features are only available with PDF output and only if the
new output implementation based on the intermediate format (PDFDocumentHandler) is used.
Accessibility (Tagged PDF) is not supported by the legacy PDFRenderer.
</li>
</ul>
</section>
<section id="links">
<title>Related Links</title>
<p>
We don't provide a comprehensive guide to create accessible documents. Below are some
links with additional resources around the topic.
Many resources providing guidance about creating accessible documents can be found on the
web. Here are a few links, along with additional resources around the topic:
</p>
<ul>
<li><a href="pdfa.html">PDF/A support in Apache FOP</a></li>
<li><a href="http://www.section508.gov/">US Government - Website on Section 508</a></li>
<li><a href="http://en.wikipedia.org/wiki/Accessibility">Wikipedia on Accessibility in general</a></li>
<li><a href="http://en.wikipedia.org/wiki/Portable_Document_Format#Accessibility">Wikipedia on Accessibility in PDF</a></li>
<li>
<a href="http://partners.adobe.com/public/developer/en/pdf/PDFReference.pdf">PDF Reference 1.4</a>
(lookup chapters 9.7 "Tagged PDF" and 9.8 "Accessibility Support")
<a href="http://partners.adobe.com/public/developer/en/pdf/PDFReference.pdf">PDF
Reference 1.4</a> (look up chapters 9.7 "Tagged PDF" and 9.8 "Accessibility Support")
</li>
<li><a href="pdfa.html">PDF/A support in Apache FOP</a></li>
<li><a href="http://wiki.apache.org/xmlgraphics-fop/PDF_Accessibility">Developer-oriented details on the accessibility features (on the Wiki)</a></li>
</ul>
</section>